Yea i got a new phone and it will not connect to the internet?

i got a blackjack 2 and i have unlimited messaging plan when i go to send a pic are get on my yahoo are aim it want do it but i have full singnal but not the 3g signal i dont have to have 3g signal to get on yahoo are send pics are videos so why want it do it i send something and it says check profile settings ther is only one option in profile settings and it is already selected so what do i do is ther a master reset just answer that question and i think it will fix it try to find out for me if ther is a mater reset are something thanx